| Last updated
The game at the Tottenham Hotspur Stadium went to penalties after Erik Lamela cancelled Timo Werner's opening goal with a strike seven minutes from time.
Mount stepped up to take Chelsea's fifth penalty but missed to hand the hosts the win and secure progression to the next round for Jose Mourinho's men.
Spurs players celebrated their triumph with goalkeeper Hugo Lloris but Dier immediately went over to his England teammate, who was understandably gutted.
It was a brilliant gesture from Dier - we're just hoping he washed his hands after he nipped to the toilet as "nature called" while the match was going on in the second half.
As if missing the penalty wasn't bad enough, Mason Mount has just found out that Eric Dier didn't wash his hands pic.twitter.com/eQIwwjAHt6- ODDSbible (@ODDSbible) September 29, 2020
21-year-old Spurs defender Japhet Tanganga was also seen consoling Mount after his penalty miss meant Chelsea lost 5-4 on spot-kicks.
Interestingly, Werner, having opened his account for the Blues in the game, did not assume duties from 12 yards despite being a prolific penalty taker during his time at RB Leipzig.
According to manager Frank Lampard, the German was suffering from cramp and did not feel he could take one.
"We spoke to the players," manager Lampard said after the game as per TeamTalk.
"You work on penalties and try and have a plan but it's very difficult to know.
"Timo had some cramp at the end and Timo would have probably taken one so we had to adjust around that."
Chosen for YouChosen for You
Most Read StoriesMost Read